Apparatus for cleaning loose materials



J. C. NELMS Sept. 10, 1940.

APPARATUS FOR CLEANING." LOOSE MATERIALS Filed April 21, 19,39 "3 Sheets-Sheet l INVENTOR. JOSEPH C. NELMS a ATTORNEY.

Sept. 10, 1940. J. NELMS 2,214,434

APPARATUS FOR CLEANING LOOSE MATERIALS Filed A il 21-, 1939 s Sheets-Sheet 2 INVENTOR. JOSEPH C. NELMS @ATTORNEY.

Sept. 10, 1940. J C, NELMS 2,214,434

- APPARATUS FOR cwmme LOOSE MATERIALS Filed April 21, 1939 3 Sheets-Sheet 3 y/o-u z/ 0 Fig.4 INVENTOR JOSEPH c. NELMS BY 8 @ATTORNEY.

Patented Sept. 10, 1940 APPARATUS FOR CLEANING LOOSE MATERIALS Joseph C. Nelms, Cleveland, Ohio Application April 21, 1938, Serial No. 203,325

4 Claims.

This invention relates toan apparatus for cleaning loose materials and removing the dust therefrom, and particularly to an apparatus for de-dusting coal when the coal is either wet or dry.

Oneof the principal objects of the present invention is to clean the coal or other loose material by causing the material to fall as a uniformly distributed stream, loosening the particles of the material with respect to each other during their fall so as to expose as much of their area as possible, and discharging a plurality of high velocity air streams across the falling stream of coal while the particles are in loose condition, and concurrently stirring the stream and wiping off the fine particles and dust from the larger particles of material and then carrying away the dust and fine particles by the air streams while collecting the coarser and cleaned particles at a location farther along the path of fall of the material.

Another objectis to provide a durable and inexpensive apparatus for efiecting the method above described.

Another object isto provide an apparatus which may be adjusted for operating properly in connection with various sizes ofloose materials in various conditions of wetness and dryness.

Other objects and advantages will become apparent from the followingspecification, wherein reference is made to the drawings, in which:

Fig. 1 is a vertical sectional view of an apparatus embodying the principles of the present invention and is taken on a plane indicated by the line Il in Fig. 2; V

Fig. 2 is a vertical sectional view taken on a plane indicated by the line 2-2 in Fig. 1;

Fig. 3 is a vertical sectional view taken on a plane indicated by the line 3-3 in Fig. 1;

Fig. 4 is an enlarged fragmentary side elevation of a portion of the apparatus illustrated in Fig. l; and

Fig. 5 is a sectional view taken on a plane indicated by the line 5-5 in Fig. 4.

For the'purposes of illustration, the apparatus is described herein in connection with the separation of dust from coal which is in either a wet or dry condition, the application of the apparatus to other materials being readily apparent from the exemplary description.

Referring to the drawings, a preferred form of the apparatus comprises a feed chute l which is open at the bottom for discharging the coal to be cleaned and de-dusted. At the bottom of the chute I is a housing 2 which encloses a revolving door 3 which operates as an effective air seal while at the same time receiving materials from the chute I and discharging the same into a feeding throat 4 arranged beneath the rigg g 1. 1 rev l ing d orfirre erfi h a large number of closely spaced paddles or door portions 5 so that the material is discharged into the throat 4 from the door in a nearly uniform and continuous stream instead of in successive heavy masses.

In the throat 4, beneath the revolving door, is a downwardly sloping'baffle 6 which receives the material discharged by the revolving door and thus temporarily impedes its fall and causes it to continue to fall thereafter as a more nearly uniform stream. Belowthe level of the baflle 6, in the throat 4, is a bafile l which slopes downwardly and is serrated, as better illustrated in Fig. 5, at its lower edge so as to further render the stream more nearly uniform in its flow and to cause the streamof material passing thereover to be more nearly sinuous or serpentine, in horizontal cross section. Such a horizontal cross section results in a. greater exposed surface area for a given volume of material than does a stream of rectangular cross section. Beneath the throat 4 is a separating chamber 8 in which the material is cleaned and the dust isseparated therefrom. I

' In the chamber 8, directly beneath the throat t, are a plurality of grids 9, each of'which grids comprises a horizontally extending row of radially spaced rods Ill. The rods ii] may extend entirely across the chamber 8 and the rows of rods extend forwardly and rearwardly of the chamber 8. The grids 9 or rows of rods are spaced vertically from each other, and the rods of each grid are offset, or staggered, forwardly and rearwardly of the compartment 8 with respect to the rods of adjacent grids. The spacing of the grids vertically is slightly less than the spacing of adjacent rods of each grid from each other so that each rod forms with the-nearest adjacent rods of the adjacent grid a substantially equilateral triangle.

By virtue of this arrangement, all of the passages between all of the rods of the tier of grids are substantially the same size.

As coal or loose material discharged from the bafiie 1 passes downwardly through the grids, each particle follows a sinuous path, which sinu- -ates forwardly and rearwardly of the compartment 8, and the mass of material is divided into a plurality of smaller streams which are reunited and subdivided successively and progressively until the material passes out of the bottom of the grid. By virtue of this arrangement, the particles of material are loosened from each other so as to expose a large surface area, each particle of material follows a longer path than it would were no grids provided, each particle is delayed in its downward travel by being temporarily impeded and released, and each particle is subjected to a stirring and rubbing action, both against other particles and against the rods themselves. It is apparent that, with the material in this condition, air currents may be more effectively employed for removing the dust and fine material.

In order to carry away the dust and fine material which are mechanically separated and knocked loose, and also to assist in the separation, the material is subjected to a plurality of high velocity air streams or blasts of air as it passes downwardly through the grids. These air streams are directed substantially horizontally and in the general direction of the rows of rods, that is, horizontally from the front toward the rear of the chamber 8. For providing the air streams, a suitable blower I I having an expanding discharge throat I 2 is provided, the discharge end of the throat I2 entering the chamber 8 immediately adjacent the grids 9. In the discharge end of the throat I2 are a plurality of'individually adjustable dampers I 3, the dampers preferably being arranged in pairs and hinged at their leading edges, that is, the edges facing toward the oncoming air stream, as indicated at I4. At their opposite or freeends, the dampers I3 are slotted so that they partially surround a suitable screw threaded rod I5 on which are arranged pairs of adjusting nuts I6, these nuts being arranged tocooperate with their associated dampers so as to adjust the position of the trailing edges of the damper. These adjustments obviously control the intensity of the air passing between adjacent dampers and discharging onto the material.

Directional vanes I! may be provided in the duct I 2 so as to break up eddy currents and cause the air passing between the baffles I3 to flow in a uniform direction. These vanes extend from top to bottom of the duct I2 and are spaced transversely of the duct from each other.

In the form illustrated, provision is made for three separate air streams, these air streams or blasts being spaced vertically from each other, being preferably coextensive with the width of the chamber 8, and being directed generally rearwardly of the chamber 8 in the direction of the rows of rods I0. The air streams delivered are of sufficient intensity to penetrate completely the stream of falling material and to pass entirely therethrough and into the rear part of the chamber 8, thus carrying away dusts and fines which have been loosened mechanically and also loosening and carrying away the fines that may be clinging to the particles of material.

It should be noted that the baffle I is arranged so that the material is discharged onto the grids near the forward portion, or adjacent the zone of introduction of the air blasts, because the air blasts tend to cause the stream of falling materials to spread or migrate toward the rear of the grits or chamber 8. By discharging the material near the front of the grids only, better distribution of the materials over the grids fore and aft of the chamber 8 is provided. The cham-' ber 8 preferably has downwardly convergent bottom walls I8 which open into a housing I9 in which is a revolving door and air seal 28, which corresponds in operation tothe door 3 heretofore described, and which is operative to discharge the material into a suitable dischargechute 2| without permitting the escape of air. The revolving doors 3 and 28 are preferably driven in timed re lation by a suitable motive power means 25.

As better illustrated in Fig. 2, the grids are preferably formed with steel end plates 26 so that if a wider chamber 8 is to be used for a larger capacity apparatus, any number of grid assemblies may be placed end to end across the chamber 8 so that the assembled grids extend the full width of the associated chamber 8. In the form illustrated, which is a relatively small capacity apparatus, the chamber 8 is only of suit.- cient width to receive one set of grids. In the chamber 8, to the rear of and aligned with the grids 9, is a baffle 30 which has a face 3| exposed toward the grids, the face 3| sloping upwardly and rearwardly of the chamber. The baflie 38 is positioned with its rear walls in spaced relation to the rear wall 32 of the chamber 8, thus defining a passage 33, so that any loose material of sumcient coarseness that it is not carried out by the air streams, may fall back onto the wall 32, may pass downwardly behind the bafile 30 and into the revolving door 28.

superposed on the chamber 8 is a communicating expanding chamber 35, one wall 36 of which preferably forms a continuation of the wall 32. The front and rear walls of the chamber 35 are divergent upwardly partway of their length, then parallel partway of their length, as indicated at 31, and then convergent upwardly for the remainder of their length, as indicated at 38. Like- 35 are divergent from the top of the chamber 8 upwardly partway of their length and then continue as substantially parallel wall portions 48 for the remainder of their length. At the top of the chamber 35 is a discharge conduit 4i, through which the dust-laden air from the chamber 35 is exhausted.

For providing sub-atmospheric pressure in the conduit 5| a suitable blower 42 and Venturi nozzle 43 may be provided, or any other suitable suction means may be used.

In operation, the heavy blasts of air passing through the grids and falling material strike the face 3| of the baffle 3|], and these dust-laden fiected by the baflle and to distribute them more uniformly across the interior of the chamber 35. Due to the increased horizontal cross sectional area of the chamber 35, as the material passes upwardly from the chamber 8, the air velocity is reduced and coarser particles can drop back into the chamber 8. However, these particles are generally intercepted by the incoming air streams until such time as they drop back to the rear of the bailles 38 and 45, after which they may settle down into the chamber 8.

In order to assist in the control of the coarseness of the material carried out of the chamber 35, the cross sectional area of the chamber may be increased or reduced. For this purpose, auxiliary walls 58, 5| and 52 are provided, the wall 58 being hingedly connected to the wall 38 at one end, and the wall 32 being hingedly connected to a suitable bracket 53 on the wall 38 at one end of the auxiliary wall 52. The auxiliary wall 5| in turn is hingedly connected at its ends to the other ends of the walls '50 and 52, respectively.

A suitable rod 54 extends from the hinge connection between the walls 5| and 52 to the outside of the chamber 35 so that the position of the walls 58, 5| and 52 can be adjusted by the rod to give the desired cross sectional area. Thus,

these independent controls, a wide range of adjustment is possible. For example, the mere change in the air streams would cause a concurrent change in the fineness of the particles carried off through the conduit 4|. However, different intensity air streams must be used for difierent sizes of coal. Yet, it may be desirable that the fines be of the same sizes in all such instances. To'meet this wide range of conditions, the cross sectional area of the expanding chamber 35 maybe varied by the walls 50, 5! and 52 without in any manner changing the immediate effect of the air streams in the chamber 8.

In the form illustrated, the apparatus can clean and de-dust about 22.5 tons of coal perhour. The length of the portions 31 of the chamber 35 is about three feet, the remainder of the drawing being substantially in proportion. The volumetric discharge of air into the chamber 8 and out of the exhaust conduit 4| may be about 2,000 cubic feet per minute. The doors 3 and 20 preferably have ten blades each, so that the material discharged thereby is discharged more nearly as a uniform stream, as it is found that fewer blades cause a pulsation in the air streams, due to heavy masses temporarily blocking the air streams to which they are subjected. Air supplied through the duct i2 is in a sufiicient volume to provide about a 3" water level gauge pressure therein.

In using the apparatus for cleaning coal of minus in size, about 2,000 cubic feet'of air per minute is supplied at a velocity of about 3,756 feet per minute at the dampers i3. About 90% of the air passing through the falling coal passes up the sloping face 3! of the baifie 30, and about 10% passes between the battle and the wall 32 to the passage 33 and acts as a scavenging current. As the size of the expanding chamber 35 is decreased in cross section, there is an increase in the size of the particles carried out through the conduits 4!, assuming the other conditions remain the same. With an increase in the cross sectional area of the chamber 35, there is a de- I crease in the size of the particles carried out.

While I have described a preferred embodiment of my invention and a simple and effective apparatus for practicing the method hereinbefore described, it is apparent that various changes and modifications may be made in the specific structure illustrated without departing from the invention as defined in the claims.

Having thus described my-invention, I claim:

1. An apparatus for cleaning and removing dust from loose materials comprising a chamber having an inlet passage at its upper portion and a discharge passage at the bottom portion, a'plurality of grids extending across the chamber and arranged in vertically spaced relation to each other and positioned between the passages and in the path of the falling material, means for directing a relatively high velocity air stream into the chamber generally rearwardly thereof across the path of falling material, a bafiie rearwardly of said grids from the air directing means and sloping upwardlyrearwardly from the grids, the said baffle being spaced from the rear wall of the chamber so that particles carried beyond and over the baflle can fall rearwardly therefrom to the discharge passage of the chamber, and means for conducting air from said chamber at a point remote from said grids and bafiie.

2. An apparatus for cleaning and removing dust from loose materials and comprising a chamber having an inlet passage at its upper portion for rality of grids extending across the chamber and arranged in vertically spaced relation to each other and positioned between the passages in the path of material to be followed by material falling from the inlet passage to the outlet passage, means for directing a relatively high velocity air stream into the chamber generally rearwardly thereof across the said path, a baffle rearwardly from said grids spaced from the front and rear walls of the chamber and sloping upwardly rearwardly of the chamber, an expansion compartment above said chamber and in communication at its lower end with the upper portion of the chamber, a bafiie in said expansion compartment, spaced from the front and rear walls thereof and so aligned with the sloping face of the first baffle as to lie in the path of air deflected from said sloping face of the first baffle, and means for conducting air from said expansion compartment.

3. An apparatus for cleaning and removing dust from loose materials and comprising a chamber having an inlet passage at its upper portion for admitting loose materials to be cleaned into the chamber, and a discharge passage at its lower porticna plurality of grids extending across the chamber at a portion between the passages and arranged in vertically spaced relation to each other for receiving materials falling through the chamber from the inlet passage toward the outlet passage, means for admitting a blast of air into said chamber rearwardly of the chamber at the zone of the grids, damper means for dividing said blast of air into a plurality of separate streams preparatory to its discharge into the chamber, an expansion compartment above said chamber and in communication at its lower end with the upper portion of said chamber at a location rearwardly from the grids, said expansion compartment being of gradually increasing cross section for a portion of its length upwardly from said chamber, means for changing the effective horizontal cross sectional area of the expansion compartment, means for conducting air from said expansion compartment at the upper portion thereof, and means for effecting adjustment of said damper means to vary the velocity of the air streams at the zone of the grids independently of the Variation of the horizontal cross sectional area of the expansion compartment.

4. An apparatus for removing dust from loose materials, comprising Walls forming a downwardly extending chamber, means to discharge the materials into the chamber continuously as a falling stream, means in the chamber arranged to separate the stream into sub-streams at a plurality of points along the paths of downward travel of the material, means to create and introduce a blast of air into the chamber from the front side thereof and across the region in which the'sub-streams occur, a primary baflie in the chamber rearwardly of the region of formation of said sub-streams and inclined upwardly and rearwardly therefrom, walls forming an expansion chamber around and above the baffle, a chute rearwardly from the baffle and communicating with the expansion chamber for downward discharge of particles out of the expansion chamber when projected above the primary baffle, and secondary baffie means in the expansion chamber above the primary baffle and generally aligned therewith.

' JOSEPH CHAS. NELMS. 

